Many industries such as aquaria, aquaculture, wastewater, and pool and spa rely on “clean” water for their proper operation. In these industries, “clean” is defined as water that is low in nutrients (e.g. Inorganic Nitrate, Inorganic Phosphate, Nitrite, Ammonia, Ammonium, and metals such as Copper). These nutrients cause problems in water such as excessive algae and bacteria growth, and in some cases, poisoning of livestock. In these instances, algae disperse in the water in an uncontrolled manner thereby making algae removal difficult. Thus in these industries there is a desire to remove nutrients and associated algae from the water in order to maintain “clean” water.
Despite the desire to remove nutrients and algae from water for certain applications, many industries rely on the presence of nutrients in the water for success. For example, food and biofuel industries grow algal biomass to produce their final products. This algal biomass requires a constant supply of nutrients to grow. Seaweed cultivators both filter the water of nutrients to provide clean water, and promote controlled growth of algal biomass such that the algae can be easily and efficiently harvested or otherwise removed from the water.
The rapid growth of attached macroalgae in either a filtering or cultivating application requires a turbulent air/water interface to maximize the nutrient transfer into the algae, which in the case of a waterfall is accomplished by gravity pulling a thin layer of water down a rough algal attachment surface; this requires the waterfall to be above a surrounding water surface level. A support structure for previous art waterfalls was needed to suspend the algae scrubber device above the surrounding water surface level; the support and waterfall were large and heavy because of the jolting movement of the water supply source tubing and the weight of the algal growth that was pulling downwards. Furthermore, illumination devices were in close proximity to algal attachment surfaces and had to be water resistant and heat sinked, which made them heavy and bulky also and thus requiring a more substantial frame or support. This added frame and bulk usually sat on a shelf in a sump beneath an aquarium, and provided limited access to the algae attachment surface for observation or cleaning/harvesting. Further, the entire structure of the waterfall, attached illumination devices, and water supply tubing usually took the majority of the open air space above the sump and therefore limited or eliminated access to the water below it. Thus there is a need for a simpler and space saving mounting and water delivery system for waterfall algae scrubbers and waterfall seaweed cultivators.
The illumination that drives the photosynthetic growth of the seaweed can be supplied by natural or artificial means. Light emitting diodes (LEDs) and similar artificial illumination emitters are commonly used, however they produce heat and require protection from water, especially saltwater. Common “plant-grow” hydroponic illumination units are readily available which are water resistant and even waterproof, however they usually are constructed with at least part of the enclosure being made of metal or a partially metallic material. Other waterproof illumination devices such as used for pools or boating also seal the illumination emitter from the water, but similar to hydroponic illumination units they do not protect the water itself from the metals, nor do they need to. These metals, if in continuous contact with saltwater, may slightly or rapidly corrode, and may cause serious damage to reef aquaria invertebrates. Even stainless steel is preferred to not be used. Invertebrates are very susceptible to small amounts of certain metals, and even the slightest trace of copper will kill them. Thus there is a need for a submersible non-metallic illumination device which is compact and lightweight in order to reduce the size and complexity of waterfall algae scrubbers.
For both filtration and cultivation, attachment of the macroalgae to solid surfaces is needed, and the surfaces should be rough and porous to encourage this attachment. Current rough attachment surfaces however are complex to manufacture or laborious to make manually. Thus, there is a need for algae scrubber and seaweed cultivator macroalgal attachment materials which are lower in cost and easier to manufacture.